This invention relates to an electromagnetic communication interface suitable for providing communication between a movable object, such as the sliding door of a railway carriage, and a stationary object, such as the body of the railway carriage on which the sliding door is mounted.
Mechanical communication interfaces are known. For example, in FIG. 1 there is shown in diagrammatic form a door opening system incorporating a mechanical communication interface. A railway vehicle 1 comprises a body 2 having a sliding door 3. The door is shown in a partially open position in the Figure. When the door is closed, contacts 4 complete an electrical circuit between a push-button 5 and a control circuit 6. Thus, when the door is closed, a passenger may push the button 5 and an instruction signal will pass via the mechanical contacts 4 to electrical control circuitry 6 in order to instruct a door opening mechanism 7 to open the door.
The above described door opening system incorporating the mechanical communication interface (i.e. the mechanical contacts 4) requires accurate initial setting up in view of the fact that the contacts 4 on the door 3 and the contacts 4 on the vehicle body 2 must be aligned such that they come into contact with each other when the door 3 is closed. In use, such an arrangement has proved to be unreliable and excessive maintenance is required in order to achieve the necessary operational reliability.